// Copyright 2025 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT

package issues

import (
	"bytes"
	stdctx "context"
	"encoding/json"
	"fmt"
	"strconv"
	"strings"

	"code.gitea.io/sdk/gitea"
	"code.gitea.io/tea/cmd/flags"
	"code.gitea.io/tea/modules/api"
	"code.gitea.io/tea/modules/context"
	"code.gitea.io/tea/modules/print"
	"code.gitea.io/tea/modules/utils"

	"github.com/urfave/cli/v3"
)

// CmdIssuesDependencies represents the subcommand for issue dependencies
var CmdIssuesDependencies = cli.Command{
	Name:        "dependencies",
	Aliases:     []string{"deps", "dep"},
	Usage:       "Manage issue dependencies",
	Description: "List, add, or remove dependencies for an issue",
	ArgsUsage:   "<issue index>",
	Action:      runDependenciesList,
	Commands: []*cli.Command{
		&cmdDependenciesList,
		&cmdDependenciesAdd,
		&cmdDependenciesRemove,
	},
	Flags: flags.AllDefaultFlags,
}

var cmdDependenciesList = cli.Command{
	Name:        "list",
	Aliases:     []string{"ls"},
	Usage:       "List dependencies for an issue",
	Description: "List issues that the specified issue depends on (blockers)",
	ArgsUsage:   "<issue index>",
	Action:      runDependenciesList,
	Flags:       flags.AllDefaultFlags,
}

var cmdDependenciesAdd = cli.Command{
	Name:        "add",
	Usage:       "Add a dependency to an issue",
	Description: "Make an issue depend on another issue (blocker)",
	ArgsUsage:   "<issue index> <dependency index or owner/repo#index>",
	Action:      runDependenciesAdd,
	Flags:       flags.AllDefaultFlags,
}

var cmdDependenciesRemove = cli.Command{
	Name:        "remove",
	Aliases:     []string{"rm"},
	Usage:       "Remove a dependency from an issue",
	Description: "Remove a dependency from an issue",
	ArgsUsage:   "<issue index> <dependency index or owner/repo#index>",
	Action:      runDependenciesRemove,
	Flags:       flags.AllDefaultFlags,
}

// runDependenciesList lists dependencies for an issue
func runDependenciesList(ctx stdctx.Context, cmd *cli.Command) error {
	c := context.InitCommand(cmd)
	c.Ensure(context.CtxRequirement{RemoteRepo: true})

	if cmd.Args().Len() < 1 {
		return fmt.Errorf("issue index required")
	}

	index, err := utils.ArgToIndex(cmd.Args().First())
	if err != nil {
		return err
	}

	client := api.NewClient(c.Login)
	path := fmt.Sprintf("/repos/%s/%s/issues/%d/dependencies", c.Owner, c.Repo, index)

	var deps []*gitea.Issue
	if _, err := client.Get(ctx, path, &deps); err != nil {
		return err
	}

	if len(deps) == 0 {
		fmt.Printf("Issue #%d has no dependencies\n", index)
		return nil
	}

	print.IssuesPullsList(deps, c.Output, []string{"index", "state", "title", "owner", "repo"})
	return nil
}

// runDependenciesAdd adds a dependency to an issue
func runDependenciesAdd(ctx stdctx.Context, cmd *cli.Command) error {
	c := context.InitCommand(cmd)
	c.Ensure(context.CtxRequirement{RemoteRepo: true})

	if cmd.Args().Len() < 2 {
		return fmt.Errorf("usage: tea issues dependencies add <issue index> <dependency index or owner/repo#index>")
	}

	index, err := utils.ArgToIndex(cmd.Args().First())
	if err != nil {
		return fmt.Errorf("invalid issue index: %w", err)
	}

	depOwner, depRepo, depIndex, err := parseDependencyArg(cmd.Args().Get(1), c.Owner, c.Repo)
	if err != nil {
		return err
	}

	client := api.NewClient(c.Login)
	path := fmt.Sprintf("/repos/%s/%s/issues/%d/dependencies", c.Owner, c.Repo, index)

	reqBody := api.IssueDependencyRequest{
		Owner: depOwner,
		Repo:  depRepo,
		Index: depIndex,
	}

	body, err := json.Marshal(reqBody)
	if err != nil {
		return fmt.Errorf("failed to marshal request: %w", err)
	}

	if _, err := client.Post(ctx, path, bytes.NewReader(body), nil); err != nil {
		return err
	}

	if depOwner == c.Owner && depRepo == c.Repo {
		fmt.Printf("Added dependency: issue #%d now depends on #%d\n", index, depIndex)
	} else {
		fmt.Printf("Added dependency: issue #%d now depends on %s/%s#%d\n", index, depOwner, depRepo, depIndex)
	}
	return nil
}

// runDependenciesRemove removes a dependency from an issue
func runDependenciesRemove(ctx stdctx.Context, cmd *cli.Command) error {
	c := context.InitCommand(cmd)
	c.Ensure(context.CtxRequirement{RemoteRepo: true})

	if cmd.Args().Len() < 2 {
		return fmt.Errorf("usage: tea issues dependencies remove <issue index> <dependency index or owner/repo#index>")
	}

	index, err := utils.ArgToIndex(cmd.Args().First())
	if err != nil {
		return fmt.Errorf("invalid issue index: %w", err)
	}

	depOwner, depRepo, depIndex, err := parseDependencyArg(cmd.Args().Get(1), c.Owner, c.Repo)
	if err != nil {
		return err
	}

	client := api.NewClient(c.Login)
	path := fmt.Sprintf("/repos/%s/%s/issues/%d/dependencies", c.Owner, c.Repo, index)

	reqBody := api.IssueDependencyRequest{
		Owner: depOwner,
		Repo:  depRepo,
		Index: depIndex,
	}

	body, err := json.Marshal(reqBody)
	if err != nil {
		return fmt.Errorf("failed to marshal request: %w", err)
	}

	if _, err := client.Delete(ctx, path, bytes.NewReader(body)); err != nil {
		return err
	}

	if depOwner == c.Owner && depRepo == c.Repo {
		fmt.Printf("Removed dependency: issue #%d no longer depends on #%d\n", index, depIndex)
	} else {
		fmt.Printf("Removed dependency: issue #%d no longer depends on %s/%s#%d\n", index, depOwner, depRepo, depIndex)
	}
	return nil
}

// parseDependencyArg parses a dependency argument which can be:
// - "123" or "#123" (same repo)
// - "owner/repo#123" (cross-repo)
func parseDependencyArg(arg, defaultOwner, defaultRepo string) (owner, repo string, index int64, err error) {
	// Check for cross-repo format: owner/repo#123
	// Ensure "/" comes before "#" to distinguish from same-repo "#123"
	slashIdx := strings.Index(arg, "/")
	hashIdx := strings.Index(arg, "#")
	if slashIdx != -1 && hashIdx != -1 && slashIdx < hashIdx {
		parts := strings.SplitN(arg, "#", 2)
		if len(parts) != 2 {
			return "", "", 0, fmt.Errorf("invalid dependency format: %s (expected owner/repo#index)", arg)
		}

		repoPath := parts[0]
		indexStr := parts[1]

		repoParts := strings.SplitN(repoPath, "/", 2)
		if len(repoParts) != 2 {
			return "", "", 0, fmt.Errorf("invalid dependency format: %s (expected owner/repo#index)", arg)
		}

		owner = repoParts[0]
		repo = repoParts[1]

		index, err = strconv.ParseInt(indexStr, 10, 64)
		if err != nil {
			return "", "", 0, fmt.Errorf("invalid issue index: %s", indexStr)
		}

		return owner, repo, index, nil
	}

	// Same repo format: 123 or #123
	index, err = utils.ArgToIndex(arg)
	if err != nil {
		return "", "", 0, fmt.Errorf("invalid issue index: %w", err)
	}

	return defaultOwner, defaultRepo, index, nil
}