package sdk

import (
	"fmt"
	"io"
	"os"
	"strings"
)

const (
	addMaskCmd = "add-mask"

	envCmd    = "env"
	outputCmd = "output"
	pathCmd   = "path"
	stateCmd  = "state"

	// https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#multiline-strings
	multiLineFileDelim = "234baa68-d26f-4bf9-996d-45ec3520cb95"
	multilineFileCmd   = "%s<<" + multiLineFileDelim + "\n%s\n" + multiLineFileDelim // ${name}<<${delimiter}${os.EOL}${convertedVal}${os.EOL}${delimiter}

	addMatcherCmd    = "add-matcher"
	removeMatcherCmd = "remove-matcher"

	groupCmd    = "group"
	endGroupCmd = "endgroup"

	stepSummaryCmd = "step-summary"

	debugCmd = "debug"

	noticeCmd  = "notice"
	warningCmd = "warning"
	errorCmd   = "error"

	errFileCmdFmt = "unable to write command to the environment file: %s"
)

type Action struct {
	w      io.Writer
	env    func(string) string
	fields CommandProperties
}

func New() *Action {
	return &Action{w: os.Stdout, env: os.Getenv}
}

// WithFieldsSlice includes the provided fields in log output. "f" must be a
// slice of k=v pairs. The given slice will be sorted. It panics if any of the
// string in the given slice does not construct a valid 'key=value' pair.
func (c *Action) WithFieldsSlice(f ...string) *Action {
	m := make(CommandProperties)
	for _, s := range f {
		pair := strings.SplitN(s, "=", 2)
		if len(pair) < 2 {
			panic(fmt.Sprintf("%q is not a proper k=v pair!", s))
		}

		m[pair[0]] = pair[1]
	}

	return c.WithFieldsMap(m)
}

// WithFieldsMap includes the provided fields in log output. The fields in "m"
// are automatically converted to k=v pairs and sorted.
func (c *Action) WithFieldsMap(m map[string]string) *Action {
	return &Action{
		w:      c.w,
		fields: m,
	}
}

// GetInput gets the input by the given name. It returns the empty string if the
// input is not defined.
func (c *Action) GetInput(i string) string {
	e := strings.ReplaceAll(i, " ", "_")
	e = strings.ToUpper(e)
	e = "INPUT_" + e
	return strings.TrimSpace(c.env(e))
}

// IssueCommand issues a new GitHub actions Command.
// It panics if it cannot write to the output stream.
func (c *Action) IssueCommand(cmd *Command) {
	if _, err := fmt.Fprintln(c.w, cmd.String()); err != nil {
		panic(fmt.Errorf("failed to issue command: %w", err))
	}
}

// IssueFileCommand issues a new GitHub actions Command using environment files.
// It panics if writing to the file fails.
func (c *Action) IssueFileCommand(cmd *Command) {
	e := strings.ReplaceAll(cmd.Name, "-", "_")
	e = strings.ToUpper(e)
	e = "GITHUB_" + e

	filepath := c.env(e)
	msg := []byte(cmd.Message)
	f, err := os.OpenFile(filepath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		panic(fmt.Errorf(errFileCmdFmt, err))
	}

	defer func() {
		if err := f.Close(); err != nil {
			panic(err)
		}
	}()

	if _, err := f.Write(msg); err != nil {
		panic(fmt.Errorf(errFileCmdFmt, err))
	}
}

// AddMask adds a new field mask for the given string "p". After called, future
// attempts to log "p" will be replaced with "***" in log output. It panics if
// it cannot write to the output stream.
func (c *Action) AddMask(p string) {
	// ::add-mask::<p>
	c.IssueCommand(&Command{
		Name:    addMaskCmd,
		Message: p,
	})
}

// AddMatcher adds a new matcher with the given file path. It panics if it
// cannot write to the output stream.
func (c *Action) AddMatcher(p string) {
	// ::add-matcher::<p>
	c.IssueCommand(&Command{
		Name:    addMatcherCmd,
		Message: p,
	})
}

// RemoveMatcher removes a matcher with the given owner name. It panics if it
// cannot write to the output stream.
func (c *Action) RemoveMatcher(o string) {
	// ::remove-matcher owner=<o>::
	c.IssueCommand(&Command{
		Name: removeMatcherCmd,
		Properties: CommandProperties{
			"owner": o,
		},
	})
}

// Group starts a new collapsable region up to the next ungroup invocation. It
// panics if it cannot write to the output stream.
func (c *Action) Group(t string) {
	// ::group::<t>
	c.IssueCommand(&Command{
		Name:    groupCmd,
		Message: t,
	})
}

// EndGroup ends the current group. It panics if it cannot write to the output
// stream.
func (c *Action) EndGroup() {
	// ::endgroup::
	c.IssueCommand(&Command{
		Name: endGroupCmd,
	})
}

// Debugf prints a debug-level message. It follows the standard fmt.Printf
// arguments, appending an OS-specific line break to the end of the message.
// It panics if it cannot write to the output stream.
func (c *Action) Debugf(msg string, args ...any) {
	// ::debug <c.fields>::<msg, args>
	c.IssueCommand(&Command{
		Name:       debugCmd,
		Message:    fmt.Sprintf(msg, args...),
		Properties: c.fields,
	})
}

// Noticef prints a notice-level message. It follows the standard fmt.Printf
// arguments, appending an OS-specific line break to the end of the message.
// It panics if it cannot write to the output stream.
func (c *Action) Noticef(msg string, args ...any) {
	// ::notice <c.fields>::<msg, args>
	c.IssueCommand(&Command{
		Name:       noticeCmd,
		Message:    fmt.Sprintf(msg, args...),
		Properties: c.fields,
	})
}

// Warningf prints a warning-level message. It follows the standard fmt.Printf
// arguments, appending an OS-specific line break to the end of the message.
// It panics if it cannot write to the output stream.
func (c *Action) Warningf(msg string, args ...any) {
	// ::warning <c.fields>::<msg, args>
	c.IssueCommand(&Command{
		Name:       warningCmd,
		Message:    fmt.Sprintf(msg, args...),
		Properties: c.fields,
	})
}

// Errorf prints a error-level message. It follows the standard fmt.Printf
// arguments, appending an OS-specific line break to the end of the message.
// It panics if it cannot write to the output stream.
func (c *Action) Errorf(msg string, args ...any) {
	// ::error <c.fields>::<msg, args>
	c.IssueCommand(&Command{
		Name:       errorCmd,
		Message:    fmt.Sprintf(msg, args...),
		Properties: c.fields,
	})
}

// AddPath adds the string "p" to the path for the invocation.
// It panics if it cannot write to the output file.
func (c *Action) AddPath(p string) {
	c.IssueFileCommand(&Command{
		Name:    pathCmd,
		Message: p,
	})
}

// SaveState saves state to be used in the "finally" post job entry point.
// It panics if it cannot write to the output stream.
func (c *Action) SaveState(k, v string) {
	c.IssueFileCommand(&Command{
		Name:    stateCmd,
		Message: fmt.Sprintf(multilineFileCmd, k, v),
	})
}

// AddStepSummary writes the given markdown to the job summary. If a job summary
// already exists, this value is appended.
// It panics if it cannot write to the output file.
func (c *Action) AddStepSummary(markdown string) {
	c.IssueFileCommand(&Command{
		Name:    stepSummaryCmd,
		Message: markdown,
	})
}

// SetEnv sets an environment variable.
// It panics if it cannot write to the output file.
func (c *Action) SetEnv(k, v string) {
	c.IssueFileCommand(&Command{
		Name:    envCmd,
		Message: fmt.Sprintf(multilineFileCmd, k, v),
	})
}

// SetOutput sets an output parameter.
// It panics if it cannot write to the output file.
func (c *Action) SetOutput(k, v string) {
	c.IssueFileCommand(&Command{
		Name:    outputCmd,
		Message: fmt.Sprintf(multilineFileCmd, k, v),
	})
}