package sdk

import (
	"encoding/json"
	"errors"
	"fmt"
	"os"
	"strconv"
)

// GitHubContext of current workflow.
// See: https://docs.github.com/en/actions/learn-github-actions/environment-variables
type GitHubContext struct {
	Action           string `env:"GITHUB_ACTION"`
	ActionPath       string `env:"GITHUB_ACTION_PATH"`
	ActionRepository string `env:"GITHUB_ACTION_REPOSITORY"`
	Actions          bool   `env:"GITHUB_ACTIONS"`
	Actor            string `env:"GITHUB_ACTOR"`
	APIURL           string `env:"GITHUB_API_URL,default=https://api.github.com"`
	BaseRef          string `env:"GITHUB_BASE_REF"`
	Env              string `env:"GITHUB_ENV"`
	EventName        string `env:"GITHUB_EVENT_NAME"`
	EventPath        string `env:"GITHUB_EVENT_PATH"`
	GraphqlURL       string `env:"GITHUB_GRAPHQL_URL,default=https://api.github.com/graphql"`
	HeadRef          string `env:"GITHUB_HEAD_REF"`
	Job              string `env:"GITHUB_JOB"`
	Path             string `env:"GITHUB_PATH"`
	Ref              string `env:"GITHUB_REF"`
	RefName          string `env:"GITHUB_REF_NAME"`
	RefProtected     bool   `env:"GITHUB_REF_PROTECTED"`
	RefType          string `env:"GITHUB_REF_TYPE"`

	Repository      string `env:"GITHUB_REPOSITORY"`
	RepositoryOwner string `env:"GITHUB_REPOSITORY_OWNER"`

	RetentionDays int64  `env:"GITHUB_RETENTION_DAYS"`
	RunAttempt    int64  `env:"GITHUB_RUN_ATTEMPT"`
	RunID         int64  `env:"GITHUB_RUN_ID"`
	RunNumber     int64  `env:"GITHUB_RUN_NUMBER"`
	ServerURL     string `env:"GITHUB_SERVER_URL,default=https://github.com"`
	SHA           string `env:"GITHUB_SHA"`
	StepSummary   string `env:"GITHUB_STEP_SUMMARY"`
	Workflow      string `env:"GITHUB_WORKFLOW"`
	Workspace     string `env:"GITHUB_WORKSPACE"`

	// Event is populated by parsing the file at EventPath, if it exists.
	Event map[string]any
}

// Context returns the context of current action with the payload object
// that triggered the workflow
func (c *Action) Context() (*GitHubContext, error) {
	var merr error
	context := &GitHubContext{
		APIURL:     "https://api.github.com",
		GraphqlURL: "https://api.github.com/graphql",
		ServerURL:  "https://github.com",
	}

	if v := c.env("GITHUB_ACTION"); v != "" {
		context.Action = v
	}
	if v := c.env("GITHUB_ACTION_PATH"); v != "" {
		context.ActionPath = v
	}
	if v := c.env("GITHUB_ACTION_REPOSITORY"); v != "" {
		context.ActionRepository = v
	}
	if v, err := parseBool(c.env("GITHUB_ACTIONS")); err == nil {
		context.Actions = v
	} else {
		merr = errors.Join(merr, err)
	}
	if v := c.env("GITHUB_ACTOR"); v != "" {
		context.Actor = v
	}
	if v := c.env("GITHUB_API_URL"); v != "" {
		context.APIURL = v
	}
	if v := c.env("GITHUB_BASE_REF"); v != "" {
		context.BaseRef = v
	}
	if v := c.env("GITHUB_ENV"); v != "" {
		context.Env = v
	}
	if v := c.env("GITHUB_EVENT_NAME"); v != "" {
		context.EventName = v
	}
	if v := c.env("GITHUB_EVENT_PATH"); v != "" {
		context.EventPath = v
	}
	if v := c.env("GITHUB_GRAPHQL_URL"); v != "" {
		context.GraphqlURL = v
	}
	if v := c.env("GITHUB_HEAD_REF"); v != "" {
		context.HeadRef = v
	}
	if v := c.env("GITHUB_JOB"); v != "" {
		context.Job = v
	}
	if v := c.env("GITHUB_PATH"); v != "" {
		context.Path = v
	}
	if v := c.env("GITHUB_REF"); v != "" {
		context.Ref = v
	}
	if v := c.env("GITHUB_REF_NAME"); v != "" {
		context.RefName = v
	}
	if v, err := parseBool(c.env("GITHUB_REF_PROTECTED")); err == nil {
		context.RefProtected = v
	} else {
		merr = errors.Join(merr, err)
	}
	if v := c.env("GITHUB_REF_TYPE"); v != "" {
		context.RefType = v
	}

	if v := c.env("GITHUB_REPOSITORY"); v != "" {
		context.Repository = v
	}
	if v := c.env("GITHUB_REPOSITORY_OWNER"); v != "" {
		context.RepositoryOwner = v
	}

	if v, err := parseInt(c.env("GITHUB_RETENTION_DAYS")); err == nil {
		context.RetentionDays = v
	} else {
		merr = errors.Join(merr, err)
	}
	if v, err := parseInt(c.env("GITHUB_RUN_ATTEMPT")); err == nil {
		context.RunAttempt = v
	} else {
		merr = errors.Join(merr, err)
	}
	if v, err := parseInt(c.env("GITHUB_RUN_ID")); err == nil {
		context.RunID = v
	} else {
		merr = errors.Join(merr, err)
	}
	if v, err := parseInt(c.env("GITHUB_RUN_NUMBER")); err == nil {
		context.RunNumber = v
	} else {
		merr = errors.Join(merr, err)
	}
	if v := c.env("GITHUB_SERVER_URL"); v != "" {
		context.ServerURL = v
	}
	if v := c.env("GITHUB_SHA"); v != "" {
		context.SHA = v
	}
	if v := c.env("GITHUB_STEP_SUMMARY"); v != "" {
		context.StepSummary = v
	}
	if v := c.env("GITHUB_WORKFLOW"); v != "" {
		context.Workflow = v
	}
	if v := c.env("GITHUB_WORKSPACE"); v != "" {
		context.Workspace = v
	}

	if context.EventPath != "" {
		eventData, err := os.ReadFile(context.EventPath)
		if err != nil && !os.IsNotExist(err) {
			return nil, fmt.Errorf("could not read event file: %w", err)
		}
		if eventData != nil {
			if err := json.Unmarshal(eventData, &context.Event); err != nil {
				return nil, fmt.Errorf("failed to unmarshal event payload: %w", err)
			}
		}
	}

	return context, merr
}

func parseBool(v string) (bool, error) {
	if v == "" {
		return false, nil
	}
	return strconv.ParseBool(v)
}

func parseInt(v string) (int64, error) {
	if v == "" {
		return 0, nil
	}
	return strconv.ParseInt(v, 10, 64)
}