package tools

import (
	"context"
	"encoding/json"
	"fmt"

	"gitea.d-ma.be/mathias/gitea-mcp/internal/allowlist"
	"gitea.d-ma.be/mathias/gitea-mcp/internal/gitea"
	"gitea.d-ma.be/mathias/gitea-mcp/internal/registry"
)

type PRMerge struct {
	c *gitea.Client
	a *allowlist.Allowlist
}

func NewPRMerge(c *gitea.Client, a *allowlist.Allowlist) *PRMerge {
	return &PRMerge{c: c, a: a}
}

func (t *PRMerge) Descriptor() registry.ToolDescriptor {
	return registry.ToolDescriptor{
		Name:        "pr_merge",
		Description: "Merge a pull request. style: merge (default), squash, or rebase.",
		InputSchema: json.RawMessage(`{
			"type":"object",
			"properties":{
				"owner":{"type":"string"},
				"name":{"type":"string"},
				"index":{"type":"integer","minimum":1},
				"style":{"type":"string","enum":["merge","squash","rebase"]},
				"merge_message_title":{"type":"string"},
				"merge_message_field":{"type":"string"}
			},
			"required":["owner","name","index"]
		}`),
	}
}

type prMergeArgs struct {
	Owner string `json:"owner"`
	Name  string `json:"name"`
	Index int    `json:"index"`
	Style string `json:"style"`
	Title string `json:"merge_message_title"`
	Body  string `json:"merge_message_field"`
}

func (t *PRMerge) Call(ctx context.Context, raw json.RawMessage) (json.RawMessage, error) {
	var args prMergeArgs
	if err := parseArgs(raw, &args); err != nil {
		return nil, err
	}
	if err := t.a.Check(args.Owner); err != nil {
		return nil, err
	}
	if args.Index < 1 {
		return nil, fmt.Errorf("index must be >= 1: %w", gitea.ErrValidation)
	}

	style := args.Style
	if style == "" {
		style = "merge"
	}

	if err := t.c.MergePullRequest(ctx, args.Owner, args.Name, args.Index, gitea.MergePRArgs{
		Do:    style,
		Title: args.Title,
		Body:  args.Body,
	}); err != nil {
		return nil, err
	}

	return textOK(map[string]any{"merged": true})
}