package issue

import (
	"context"
	"fmt"
	"net/url"

	"gitea.com/gitea/gitea-mcp/pkg/annotation"
	"gitea.com/gitea/gitea-mcp/pkg/gitea"
	"gitea.com/gitea/gitea-mcp/pkg/params"
	"gitea.com/gitea/gitea-mcp/pkg/slim"
	"gitea.com/gitea/gitea-mcp/pkg/to"
	"gitea.com/gitea/gitea-mcp/pkg/tool"

	gitea_sdk "code.gitea.io/sdk/gitea"
	"github.com/mark3labs/mcp-go/mcp"
	"github.com/mark3labs/mcp-go/server"
)

// issueWithAssets / commentWithAssets wrap the SDK types to capture the
// `assets` field that the SDK currently drops on these endpoints.
type issueWithAssets struct {
	gitea_sdk.Issue
	Assets []*gitea_sdk.Attachment `json:"assets"`
}

type commentWithAssets struct {
	gitea_sdk.Comment
	Assets []*gitea_sdk.Attachment `json:"assets"`
}

var Tool = tool.New()

const (
	ListRepoIssuesToolName = "list_issues"
	IssueReadToolName      = "issue_read"
	IssueWriteToolName     = "issue_write"
)

var (
	ListRepoIssuesTool = mcp.NewTool(
		ListRepoIssuesToolName,
		mcp.WithToolAnnotation(annotation.ReadOnly("List repository issues")),
		mcp.WithString("owner", mcp.Required(), mcp.Description(params.OwnerDesc)),
		mcp.WithString("repo", mcp.Required(), mcp.Description(params.RepoDesc)),
		mcp.WithString("state", mcp.DefaultString("all")),
		mcp.WithArray("labels", mcp.Description("label name filter"), mcp.Items(map[string]any{"type": "string"})),
		mcp.WithString("since", mcp.Description("updated after ISO 8601")),
		mcp.WithString("before", mcp.Description("updated before ISO 8601")),
		mcp.WithNumber("page", mcp.Description(params.PageDesc), mcp.DefaultNumber(1)),
		mcp.WithNumber("per_page", mcp.Description(params.PaginationDesc), mcp.DefaultNumber(30)),
	)

	IssueReadTool = mcp.NewTool(
		IssueReadToolName,
		mcp.WithDescription("Read issue: details, comments, or labels."),
		mcp.WithToolAnnotation(annotation.ReadOnly("Read issue details")),
		mcp.WithString("method", mcp.Required(), mcp.Enum("get", "get_comments", "get_labels")),
		mcp.WithString("owner", mcp.Required(), mcp.Description(params.OwnerDesc)),
		mcp.WithString("repo", mcp.Required(), mcp.Description(params.RepoDesc)),
		mcp.WithNumber("issue_number", mcp.Required()),
	)

	IssueWriteTool = mcp.NewTool(
		IssueWriteToolName,
		mcp.WithDescription("Write issues: create, update, manage comments and labels."),
		mcp.WithToolAnnotation(annotation.Write("Create or update issues, comments, and labels")),
		mcp.WithString("method", mcp.Required(), mcp.Enum("create", "update", "add_comment", "edit_comment", "add_labels", "remove_label", "replace_labels", "clear_labels")),
		mcp.WithString("owner", mcp.Required(), mcp.Description(params.OwnerDesc)),
		mcp.WithString("repo", mcp.Required(), mcp.Description(params.RepoDesc)),
		mcp.WithNumber("issue_number", mcp.Description("required except for 'create'")),
		mcp.WithString("title", mcp.Description("required for 'create'")),
		mcp.WithString("body", mcp.Description("required for 'create'/'add_comment'/'edit_comment'")),
		mcp.WithArray("assignees", mcp.Items(map[string]any{"type": "string"})),
		mcp.WithNumber("milestone"),
		mcp.WithString("state", mcp.Enum("open", "closed", "all")),
		mcp.WithNumber("commentID", mcp.Description("for 'edit_comment'")),
		mcp.WithArray("labels", mcp.Description("label IDs"), mcp.Items(map[string]any{"type": "number"})),
		mcp.WithNumber("label_id", mcp.Description("for 'remove_label'")),
		mcp.WithString("ref", mcp.Description("branch to associate")),
		mcp.WithString("deadline", mcp.Description("ISO 8601")),
		mcp.WithBoolean("remove_deadline"),
	)
)

func init() {
	Tool.RegisterRead(server.ServerTool{
		Tool:    ListRepoIssuesTool,
		Handler: listRepoIssuesFn,
	})
	Tool.RegisterRead(server.ServerTool{
		Tool:    IssueReadTool,
		Handler: issueReadFn,
	})
	Tool.RegisterWrite(server.ServerTool{
		Tool:    IssueWriteTool,
		Handler: issueWriteFn,
	})
}

func issueReadFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	args := req.GetArguments()
	method, err := params.GetString(args, "method")
	if err != nil {
		return to.ErrorResult(err)
	}
	switch method {
	case "get":
		return getIssueByIndexFn(ctx, req)
	case "get_comments":
		return getIssueCommentsByIndexFn(ctx, req)
	case "get_labels":
		return getIssueLabelsFn(ctx, req)
	default:
		return to.ErrorResult(fmt.Errorf("unknown method: %s", method))
	}
}

func issueWriteFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	args := req.GetArguments()
	method, err := params.GetString(args, "method")
	if err != nil {
		return to.ErrorResult(err)
	}
	switch method {
	case "create":
		return createIssueFn(ctx, req)
	case "update":
		return editIssueFn(ctx, req)
	case "add_comment":
		return createIssueCommentFn(ctx, req)
	case "edit_comment":
		return editIssueCommentFn(ctx, req)
	case "add_labels":
		return addIssueLabelsFn(ctx, req)
	case "remove_label":
		return removeIssueLabelFn(ctx, req)
	case "replace_labels":
		return replaceIssueLabelsFn(ctx, req)
	case "clear_labels":
		return clearIssueLabelsFn(ctx, req)
	default:
		return to.ErrorResult(fmt.Errorf("unknown method: %s", method))
	}
}

func getIssueByIndexFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	owner, err := params.GetString(req.GetArguments(), "owner")
	if err != nil {
		return to.ErrorResult(err)
	}
	repo, err := params.GetString(req.GetArguments(), "repo")
	if err != nil {
		return to.ErrorResult(err)
	}
	index, err := params.GetIndex(req.GetArguments(), "issue_number")
	if err != nil {
		return to.ErrorResult(err)
	}
	var issue issueWithAssets
	path := fmt.Sprintf("repos/%s/%s/issues/%d", url.PathEscape(owner), url.PathEscape(repo), index)
	if _, err := gitea.DoJSON(ctx, "GET", path, nil, nil, &issue); err != nil {
		return to.ErrorResult(fmt.Errorf("get %v/%v/issue/%v err: %v", owner, repo, index, err))
	}
	m := slimIssue(&issue.Issue)
	m["body"] = slim.BodyWithAttachments(issue.Body, issue.Assets)
	return to.TextResult(m)
}

func listRepoIssuesFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	owner, err := params.GetString(req.GetArguments(), "owner")
	if err != nil {
		return to.ErrorResult(err)
	}
	repo, err := params.GetString(req.GetArguments(), "repo")
	if err != nil {
		return to.ErrorResult(err)
	}
	state, ok := req.GetArguments()["state"].(string)
	if !ok {
		state = "all"
	}
	labels := params.GetStringSlice(req.GetArguments(), "labels")
	page, pageSize := params.GetPagination(req.GetArguments(), 30)
	opt := gitea_sdk.ListIssueOption{
		State:  gitea_sdk.StateType(state),
		Labels: labels,
		ListOptions: gitea_sdk.ListOptions{
			Page:     page,
			PageSize: pageSize,
		},
	}
	if t := params.GetOptionalTime(req.GetArguments(), "since"); t != nil {
		opt.Since = *t
	}
	if t := params.GetOptionalTime(req.GetArguments(), "before"); t != nil {
		opt.Before = *t
	}
	client, err := gitea.ClientFromContext(ctx)
	if err != nil {
		return to.ErrorResult(fmt.Errorf("get gitea client err: %v", err))
	}
	issues, _, err := client.ListRepoIssues(owner, repo, opt)
	if err != nil {
		return to.ErrorResult(fmt.Errorf("get %v/%v/issues err: %v", owner, repo, err))
	}
	return to.TextResult(slimIssues(issues))
}

func createIssueFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	owner, err := params.GetString(req.GetArguments(), "owner")
	if err != nil {
		return to.ErrorResult(err)
	}
	repo, err := params.GetString(req.GetArguments(), "repo")
	if err != nil {
		return to.ErrorResult(err)
	}
	title, err := params.GetString(req.GetArguments(), "title")
	if err != nil {
		return to.ErrorResult(err)
	}
	body, err := params.GetString(req.GetArguments(), "body")
	if err != nil {
		return to.ErrorResult(err)
	}
	client, err := gitea.ClientFromContext(ctx)
	if err != nil {
		return to.ErrorResult(fmt.Errorf("get gitea client err: %v", err))
	}
	opt := gitea_sdk.CreateIssueOption{
		Title: title,
		Body:  body,
	}
	opt.Assignees = params.GetStringSlice(req.GetArguments(), "assignees")
	if val, exists := req.GetArguments()["milestone"]; exists {
		if milestone, ok := params.ToInt64(val); ok {
			opt.Milestone = milestone
		}
	}
	if labelIDs, err := params.GetInt64Slice(req.GetArguments(), "labels"); err == nil {
		opt.Labels = labelIDs
	}
	if ref, ok := req.GetArguments()["ref"].(string); ok {
		opt.Ref = ref
	}
	opt.Deadline = params.GetOptionalTime(req.GetArguments(), "deadline")
	issue, _, err := client.CreateIssue(owner, repo, opt)
	if err != nil {
		return to.ErrorResult(fmt.Errorf("create %v/%v/issue err: %v", owner, repo, err))
	}

	return to.TextResult(slimIssue(issue))
}

func createIssueCommentFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	owner, err := params.GetString(req.GetArguments(), "owner")
	if err != nil {
		return to.ErrorResult(err)
	}
	repo, err := params.GetString(req.GetArguments(), "repo")
	if err != nil {
		return to.ErrorResult(err)
	}
	index, err := params.GetIndex(req.GetArguments(), "issue_number")
	if err != nil {
		return to.ErrorResult(err)
	}
	body, err := params.GetString(req.GetArguments(), "body")
	if err != nil {
		return to.ErrorResult(err)
	}
	opt := gitea_sdk.CreateIssueCommentOption{
		Body: body,
	}
	client, err := gitea.ClientFromContext(ctx)
	if err != nil {
		return to.ErrorResult(fmt.Errorf("get gitea client err: %v", err))
	}
	issueComment, _, err := client.CreateIssueComment(owner, repo, index, opt)
	if err != nil {
		return to.ErrorResult(fmt.Errorf("create %v/%v/issue/%v/comment err: %v", owner, repo, index, err))
	}

	return to.TextResult(slimComment(issueComment))
}

func editIssueFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	owner, err := params.GetString(req.GetArguments(), "owner")
	if err != nil {
		return to.ErrorResult(err)
	}
	repo, err := params.GetString(req.GetArguments(), "repo")
	if err != nil {
		return to.ErrorResult(err)
	}
	index, err := params.GetIndex(req.GetArguments(), "issue_number")
	if err != nil {
		return to.ErrorResult(err)
	}

	args := req.GetArguments()
	opt := gitea_sdk.EditIssueOption{
		Body:           params.GetPresentStringPtr(args, "body"),
		Ref:            params.GetPresentStringPtr(args, "ref"),
		Assignees:      params.GetStringSlice(args, "assignees"),
		Deadline:       params.GetOptionalTime(args, "deadline"),
		RemoveDeadline: params.GetOptionalBoolPtr(args, "remove_deadline"),
	}
	if title, ok := args["title"].(string); ok {
		opt.Title = title
	}
	if val, exists := args["milestone"]; exists {
		if milestone, ok := params.ToInt64(val); ok {
			opt.Milestone = &milestone
		}
	}
	if state, ok := args["state"].(string); ok {
		s := gitea_sdk.StateType(state)
		opt.State = &s
	}

	client, err := gitea.ClientFromContext(ctx)
	if err != nil {
		return to.ErrorResult(fmt.Errorf("get gitea client err: %v", err))
	}
	issue, _, err := client.EditIssue(owner, repo, index, opt)
	if err != nil {
		return to.ErrorResult(fmt.Errorf("edit %v/%v/issue/%v err: %v", owner, repo, index, err))
	}

	return to.TextResult(slimIssue(issue))
}

func editIssueCommentFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	owner, err := params.GetString(req.GetArguments(), "owner")
	if err != nil {
		return to.ErrorResult(err)
	}
	repo, err := params.GetString(req.GetArguments(), "repo")
	if err != nil {
		return to.ErrorResult(err)
	}
	commentID, err := params.GetIndex(req.GetArguments(), "commentID")
	if err != nil {
		return to.ErrorResult(err)
	}
	body, err := params.GetString(req.GetArguments(), "body")
	if err != nil {
		return to.ErrorResult(err)
	}
	opt := gitea_sdk.EditIssueCommentOption{
		Body: body,
	}
	client, err := gitea.ClientFromContext(ctx)
	if err != nil {
		return to.ErrorResult(fmt.Errorf("get gitea client err: %v", err))
	}
	issueComment, _, err := client.EditIssueComment(owner, repo, commentID, opt)
	if err != nil {
		return to.ErrorResult(fmt.Errorf("edit %v/%v/issues/comments/%v err: %v", owner, repo, commentID, err))
	}

	return to.TextResult(slimComment(issueComment))
}

func getIssueCommentsByIndexFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	owner, err := params.GetString(req.GetArguments(), "owner")
	if err != nil {
		return to.ErrorResult(err)
	}
	repo, err := params.GetString(req.GetArguments(), "repo")
	if err != nil {
		return to.ErrorResult(err)
	}
	index, err := params.GetIndex(req.GetArguments(), "issue_number")
	if err != nil {
		return to.ErrorResult(err)
	}
	var comments []commentWithAssets
	path := fmt.Sprintf("repos/%s/%s/issues/%d/comments", url.PathEscape(owner), url.PathEscape(repo), index)
	if _, err := gitea.DoJSON(ctx, "GET", path, nil, nil, &comments); err != nil {
		return to.ErrorResult(fmt.Errorf("get %v/%v/issues/%v/comments err: %v", owner, repo, index, err))
	}
	out := make([]map[string]any, 0, len(comments))
	for i := range comments {
		m := slimComment(&comments[i].Comment)
		m["body"] = slim.BodyWithAttachments(comments[i].Body, comments[i].Assets)
		out = append(out, m)
	}
	return to.TextResult(out)
}

func getIssueLabelsFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	owner, err := params.GetString(req.GetArguments(), "owner")
	if err != nil {
		return to.ErrorResult(err)
	}
	repo, err := params.GetString(req.GetArguments(), "repo")
	if err != nil {
		return to.ErrorResult(err)
	}
	index, err := params.GetIndex(req.GetArguments(), "issue_number")
	if err != nil {
		return to.ErrorResult(err)
	}

	client, err := gitea.ClientFromContext(ctx)
	if err != nil {
		return to.ErrorResult(fmt.Errorf("get gitea client err: %v", err))
	}
	labels, _, err := client.GetIssueLabels(owner, repo, index, gitea_sdk.ListLabelsOptions{})
	if err != nil {
		return to.ErrorResult(fmt.Errorf("get %v/%v/issues/%v/labels err: %v", owner, repo, index, err))
	}
	return to.TextResult(slim.Labels(labels))
}

func addIssueLabelsFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	owner, err := params.GetString(req.GetArguments(), "owner")
	if err != nil {
		return to.ErrorResult(err)
	}
	repo, err := params.GetString(req.GetArguments(), "repo")
	if err != nil {
		return to.ErrorResult(err)
	}
	index, err := params.GetIndex(req.GetArguments(), "issue_number")
	if err != nil {
		return to.ErrorResult(err)
	}
	labels, err := params.GetInt64Slice(req.GetArguments(), "labels")
	if err != nil {
		return to.ErrorResult(err)
	}

	client, err := gitea.ClientFromContext(ctx)
	if err != nil {
		return to.ErrorResult(fmt.Errorf("get gitea client err: %v", err))
	}
	issueLabels, _, err := client.AddIssueLabels(owner, repo, index, gitea_sdk.IssueLabelsOption{Labels: labels})
	if err != nil {
		return to.ErrorResult(fmt.Errorf("add labels to %v/%v/issue/%v err: %v", owner, repo, index, err))
	}
	return to.TextResult(slim.Labels(issueLabels))
}

func replaceIssueLabelsFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	owner, err := params.GetString(req.GetArguments(), "owner")
	if err != nil {
		return to.ErrorResult(err)
	}
	repo, err := params.GetString(req.GetArguments(), "repo")
	if err != nil {
		return to.ErrorResult(err)
	}
	index, err := params.GetIndex(req.GetArguments(), "issue_number")
	if err != nil {
		return to.ErrorResult(err)
	}
	labels, err := params.GetInt64Slice(req.GetArguments(), "labels")
	if err != nil {
		return to.ErrorResult(err)
	}

	client, err := gitea.ClientFromContext(ctx)
	if err != nil {
		return to.ErrorResult(fmt.Errorf("get gitea client err: %v", err))
	}
	issueLabels, _, err := client.ReplaceIssueLabels(owner, repo, index, gitea_sdk.IssueLabelsOption{Labels: labels})
	if err != nil {
		return to.ErrorResult(fmt.Errorf("replace labels on %v/%v/issue/%v err: %v", owner, repo, index, err))
	}
	return to.TextResult(slim.Labels(issueLabels))
}

func clearIssueLabelsFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	owner, err := params.GetString(req.GetArguments(), "owner")
	if err != nil {
		return to.ErrorResult(err)
	}
	repo, err := params.GetString(req.GetArguments(), "repo")
	if err != nil {
		return to.ErrorResult(err)
	}
	index, err := params.GetIndex(req.GetArguments(), "issue_number")
	if err != nil {
		return to.ErrorResult(err)
	}

	client, err := gitea.ClientFromContext(ctx)
	if err != nil {
		return to.ErrorResult(fmt.Errorf("get gitea client err: %v", err))
	}
	_, err = client.ClearIssueLabels(owner, repo, index)
	if err != nil {
		return to.ErrorResult(fmt.Errorf("clear labels on %v/%v/issue/%v err: %v", owner, repo, index, err))
	}
	return to.TextResult("Labels cleared successfully")
}

func removeIssueLabelFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	owner, err := params.GetString(req.GetArguments(), "owner")
	if err != nil {
		return to.ErrorResult(err)
	}
	repo, err := params.GetString(req.GetArguments(), "repo")
	if err != nil {
		return to.ErrorResult(err)
	}
	index, err := params.GetIndex(req.GetArguments(), "issue_number")
	if err != nil {
		return to.ErrorResult(err)
	}
	labelID, err := params.GetIndex(req.GetArguments(), "label_id")
	if err != nil {
		return to.ErrorResult(err)
	}

	client, err := gitea.ClientFromContext(ctx)
	if err != nil {
		return to.ErrorResult(fmt.Errorf("get gitea client err: %v", err))
	}
	_, err = client.DeleteIssueLabel(owner, repo, index, labelID)
	if err != nil {
		return to.ErrorResult(fmt.Errorf("remove label %v from %v/%v/issue/%v err: %v", labelID, owner, repo, index, err))
	}
	return to.TextResult("Label removed successfully")
}