package tools

import (
	"context"
	"encoding/base64"
	"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 FileWriteBranch struct {
	c *gitea.Client
	a *allowlist.Allowlist
}

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

func (t *FileWriteBranch) Descriptor() registry.ToolDescriptor {
	return registry.ToolDescriptor{
		Name:        "file_write_branch",
		Description: "Create or update a file on a feature branch. Branch is created from base if it doesn't exist.",
		InputSchema: json.RawMessage(`{
			"type":"object",
			"properties":{
				"owner":{"type":"string"},
				"name":{"type":"string"},
				"path":{"type":"string"},
				"content":{"type":"string"},
				"branch":{"type":"string"},
				"base":{"type":"string"},
				"message":{"type":"string"},
				"sha":{"type":"string"}
			},
			"required":["owner","name","path","content","branch","message"]
		}`),
	}
}

type fileWriteBranchArgs struct {
	Owner   string `json:"owner"`
	Name    string `json:"name"`
	Path    string `json:"path"`
	Content string `json:"content"`
	Branch  string `json:"branch"`
	Base    string `json:"base"`
	Message string `json:"message"`
	Sha     string `json:"sha"`
}

func (t *FileWriteBranch) Call(ctx context.Context, raw json.RawMessage) (json.RawMessage, error) {
	var args fileWriteBranchArgs
	if err := parseArgs(raw, &args); err != nil {
		return nil, err
	}
	if err := t.a.Check(args.Owner); err != nil {
		return nil, err
	}
	if args.Branch == "" {
		return nil, fmt.Errorf("branch is required: %w", gitea.ErrValidation)
	}
	if args.Message == "" {
		return nil, fmt.Errorf("message is required: %w", gitea.ErrValidation)
	}

	// Resolve base default if branch needs to be created
	exists, err := t.c.BranchExists(ctx, args.Owner, args.Name, args.Branch)
	if err != nil {
		return nil, err
	}
	if !exists {
		base := args.Base
		if base == "" {
			repo, err := t.c.GetRepo(ctx, args.Owner, args.Name)
			if err != nil {
				return nil, err
			}
			base = repo.DefaultBranch
		}
		if err := t.c.CreateBranch(ctx, args.Owner, args.Name, args.Branch, base); err != nil {
			return nil, err
		}
	}

	encoded := base64.StdEncoding.EncodeToString([]byte(args.Content))
	result, err := t.c.UpsertFile(ctx, args.Owner, args.Name, args.Path, gitea.UpsertFileArgs{
		Branch:  args.Branch,
		Content: encoded,
		Message: args.Message,
		Sha:     args.Sha,
	})
	if err != nil {
		return nil, err
	}

	return textOK(map[string]any{
		"path":       result.Content.Path,
		"sha":        result.Content.Sha,
		"branch":     args.Branch,
		"commit_sha": result.Commit.Sha,
		"html_url":   result.Content.HTMLURL,
	})
}